With the underside exposed I was able to trim the lower rear wing cuff and install the wing/strut plate. It will get removed when it's time for covering next summer.

The leading edge wing cuff gets put in position and (gently) tightened down with ratchet straps on every other rib.

From the inside of the wing trace the outline of the ribs and cuff supports.

The cuff is taken off the wing, and each rib is marked at 0.5", 1.5" (ribs 5-8 only), 3", and 5.5". I freehand guesstimated the centerline of my ribs and only one came out less than perfect but next time I'll use a small, flexible, see-through ruler for better centerline alignment.

Note that the 3" mark should correspond to the wing cuff support angle and the 1.5" mark should correspond to the secondary wing cuff support angle. My cuffs were about .75" too far aft and I had to move them forward to correspond to the marks.

Flip the cuff over and mark the lower part at 0.5" and 1.5".

Drill and deburr the marks, then remount the cuff. Start at the front (top) of the wing, drill and cleco the ribs (and the cuff underneath) and work aft. I found it best to start on every other rib where they were held down with a strap...

Then come back and do the ribs in between.

And work your way aft. Before you drill where the cuff support is make sure it hasn't shifted position and is still under the holes you drilled in the cuff.

Then reverse and drill/cleco the bottom.

The cuff at the wingtip will get trimmed and fit next.